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more flexible USB protocol for VNA settings/measurements

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This commit is contained in:
Jan Käberich 2022-08-06 16:22:12 +02:00
parent 74e6a439af
commit 047f6ce981
13 changed files with 203 additions and 82 deletions
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23
Software/VNA_embedded/Application/Communication/Protocol.cpp
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@ -62,7 +62,7 @@ uint16_t Protocol::DecodeBuffer(uint8_t *buf, uint16_t len, PacketInfo *info) {
/* The complete frame has been received, check checksum */
auto type = (PacketType) data[3];
uint32_t crc = *(uint32_t*) &data[length - 4];
if(type != PacketType::Datapoint) {
if(type != PacketType::VNADatapoint) {
uint32_t compare = CRC32(0, data, length - 4);
if(crc != compare) {
// CRC mismatch, remove header
@ -70,6 +70,8 @@ uint16_t Protocol::DecodeBuffer(uint8_t *buf, uint16_t len, PacketInfo *info) {
info->type = PacketType::None;
return data - buf;
}
// Valid packet, copy packet type and payload
memcpy(info, &data[3], length - 7);
} else {
// Datapoint has the CRC set to zero
if(crc != 0x00000000) {
@ -77,17 +79,19 @@ uint16_t Protocol::DecodeBuffer(uint8_t *buf, uint16_t len, PacketInfo *info) {
info->type = PacketType::None;
return data - buf;
}
// Create the datapoint
info->type = (PacketType) data[3];
info->VNAdatapoint = new VNADatapoint<32>;
info->VNAdatapoint->decode(&data[4], length - 8);
}
// Valid packet, copy packet type and payload
memcpy(info, &data[3], length - 7);
return data - buf + length;
}
uint16_t Protocol::EncodePacket(const PacketInfo &packet, uint8_t *dest, uint16_t destsize) {
int16_t payload_size = 0;
switch (packet.type) {
case PacketType::Datapoint: payload_size = sizeof(packet.datapoint); break;
// case PacketType::Datapoint: payload_size = sizeof(packet.datapoint); break;
case PacketType::SweepSettings: payload_size = sizeof(packet.settings); break;
case PacketType::Reference: payload_size = sizeof(packet.reference); break;
case PacketType::DeviceInfo: payload_size = sizeof(packet.info); break;
@ -115,6 +119,7 @@ uint16_t Protocol::EncodePacket(const PacketInfo &packet, uint8_t *dest, uint16_
case PacketType::RequestDeviceStatus:
// no payload
break;
case PacketType::VNADatapoint: payload_size = packet.VNAdatapoint->requiredBufferSize(); break;
case PacketType::None:
break;
}
@ -126,14 +131,18 @@ uint16_t Protocol::EncodePacket(const PacketInfo &packet, uint8_t *dest, uint16_
dest[0] = header;
uint16_t overall_size = payload_size + 8;
memcpy(&dest[1], &overall_size, 2);
memcpy(&dest[3], &packet, payload_size + 1); // one additional byte for the packet type
// Calculate checksum
// Further encoding uses a special case for VNADatapoint packettype
uint32_t crc = 0x00000000;
if(packet.type == PacketType::Datapoint) {
if(packet.type == PacketType::VNADatapoint) {
// CRC calculation takes about 18us which is the bulk of the time required to encode and transmit a datapoint.
// Skip CRC for data points to optimize throughput
dest[3] = (uint8_t) packet.type;
packet.VNAdatapoint->encode(&dest[4], destsize - 8);
crc = 0x00000000;
} else {
// Copy rest of the packet
memcpy(&dest[3], &packet, payload_size + 1); // one additional byte for the packet type
// Calculate the CRC
crc = CRC32(0, dest, overall_size - 4);
}
memcpy(&dest[overall_size - 4], &crc, 4);